The present embodiments relate to a method for determining an arrangement of an electric vehicle relative to a charging point and an arrangement for the determination unit for determining such an arrangement.
Electric vehicles may be inductively charged with electrical energy. For this purpose, the electric vehicle includes a secondary coil that may be inductively coupled to a primary coil of a charging point. The primary coil is normally arranged in the base of a charging point so that the electric vehicle with the secondary coil may be positioned above the primary coil. The secondary coil is appropriately located on the underbody of the electric vehicle (e.g., in the area of the front axle). The primary coil and secondary coil are to be positioned as precisely as possible one above the other for the inductive charging. The positioning tolerance is a few centimeters in the direction of travel of the electric vehicle and in the direction perpendicular to the direction of travel and parallel to the ground. The maximum angle of twist, also referred to below as the yaw angle Ψ, around the vertical axis is only a few angular degrees. It is correspondingly difficult to position the electric vehicle suitably for the inductive charging.
A method for determining an arrangement of the electric vehicle relative to the charging point is helpful in order to support a driver of the electric vehicle when approaching a position suitable for the inductive charging of the electric vehicle. The determination of the arrangement of the electric vehicle relative to the charging point is also safety-related, since a charging release (e.g., a permission to activate the charging field of the primary coil) may be effected only if the secondary coil is located within a defined tolerance range above the primary coil.
In order to determine the arrangement of the electric vehicle relative to the charging point, it is known, by an on-board time-resolution camera, to detect the position of the primary coil in the camera image and track the position over time until this position disappears under the vehicle. Due to the temporal tracking of further image elements (e.g., carriageway boundaries) and/or the incorporation of vehicle data, such as the vehicle speed or the steering angle, the relative position and the relative orientation of the primary charging coil may be calculated without a direct line of sight. However, reliability and accuracy are not yet satisfactory.